Improve archery benchmark support

- Add '\n' do diff json output adhering to jsonlines
- Add support for items_per_second metrics
- Add `--pdb` option to drop a pdb shell on uncaught exception

dev/archery/archery/benchmark/google.py

@@ -87,13 +87,14 @@ class GoogleBenchmarkObservation:
     """
 
     def __init__(self, name, real_time, cpu_time, time_unit, size=None,
-                 bytes_per_second=None, **kwargs):
+                 bytes_per_second=None, items_per_second=None, **kwargs):
         self._name = name
         self.real_time = real_time
         self.cpu_time = cpu_time
         self.time_unit = time_unit
         self.size = size
         self.bytes_per_second = bytes_per_second
+        self.items_per_second = items_per_second
 
     @property
     def is_agg(self):
@@ -118,11 +119,21 @@ class GoogleBenchmarkObservation:
     @property
     def value(self):
         """ Return the benchmark value."""
-        return self.bytes_per_second if self.size else self.time
+        if self.bytes_per_second:
+            return self.bytes_per_second
+        elif self.items_per_second:
+            return self.items_per_second
+        else:
+            return self.time
 
     @property
     def unit(self):
-        return "bytes_per_second" if self.size else self.time_unit
+        if self.bytes_per_second:
+            return "bytes_per_second"
+        elif self.items_per_second:
+            return "items_per_second"
+        else:
+            return self.time_unit
 
     def __repr__(self):
         return f"{self.value}"
@@ -147,9 +158,7 @@ class GoogleBenchmark(Benchmark):
         _, runs = partition(lambda b: b.is_agg, runs)
         self.runs = sorted(runs, key=lambda b: b.value)
         unit = self.runs[0].unit
-        # If `size` is found in the json dict, then the benchmark is reported
-        # in bytes per second
-        less_is_better = self.runs[0].size is None
+        less_is_better = not unit.endswith("per_second")
         values = [b.value for b in self.runs]
         super().__init__(name, unit, less_is_better, values)
 

dev/archery/archery/cli.py

@@ -37,10 +37,12 @@ logging.basicConfig(level=logging.INFO)
 @click.group()
 @click.option("--debug", type=bool, is_flag=True, default=False,
               help="Increase logging with debugging output.")
+@click.option("--pdb", type=bool, is_flag=True, default=False,
+              help="Invoke pdb on uncaught exception.")
 @click.option("-q", "--quiet", type=bool, is_flag=True, default=False,
               help="Silence executed commands.")
 @click.pass_context
-def archery(ctx, debug, quiet):
+def archery(ctx, debug, pdb, quiet):
     """ Apache Arrow developer utilities.
 
     See sub-commands help with `archery <cmd> --help`.
@@ -53,6 +55,10 @@ def archery(ctx, debug, quiet):
     if debug:
         logger.setLevel(logging.DEBUG)
 
+    if pdb:
+        import pdb
+        sys.excepthook = lambda t, v, e: pdb.pm()
+
 
 def validate_arrow_sources(ctx, param, src):
     """ Ensure a directory contains Arrow cpp sources. """
@@ -357,7 +363,7 @@ def benchmark_diff(ctx, src, preserve, suite_filter, benchmark_filter,
         for comparator in runner_comp.comparisons:
             regressions += comparator.regression
             json.dump(comparator, output, cls=JsonEncoder)
-            output.write('\n')
+            output.write("\n")
 
         sys.exit(regressions)